1. Field of the Invention
The present invention is directed to a device for holding and positioning an x-ray cassette in a radiological examination apparatus, sometimes referred to as an "x-ray target device."
2. Description of Related Art
German OS 30 34 282 discloses an x-ray target device having a cassette carriage for conveying an x-ray film cassette from a standby or readiness position into an exposure position and vice versa. A cassette frame for the acceptance of the x-ray film cassette is adjustable perpendicularly relative to the cassette carriage (i.e., sideways within the carriage. The cassette carriage can be conveyed into the readiness or into the exposure position via a first geared motor and a traction cable. In the exposure position, the cassette frame can be adjusted perpendicularly relative to the cassette carriage by a further geared motor that is in communication via a square shaft with a toothed belt conducted around a toothed pulley.
Two conveying paths arranged lying opposite one another for an x-ray film cassette are adjustable relative to one another via respective drives in an x-ray target device disclosed in German OS 30 36 195. One conveying path is implemented with a conveyor belt that can be driven by a third drive.
An x-ray cassette holder and positioning device is disclosed in German PS 43 32 427, which is a "parent" to the German application corresponding to the present application. As disclosed therein, a device for conveying a cassette has at least one driveable drum that enables adjustment of the cassette into or out of a readiness position, by means of frictional engagement with a cassette surface. In the readiness position, the cassette is held by two collet chucks that are oppositely adjustable relative to one another. The collet chucks are seated at a carriage that is adjustable at guides. The carriage is coupled to a cable that extends along the guides and that is conducted around deflectors. A further drive engages at the cable for the adjustment thereof. The cassette can thus be adjusted from the readiness position into an exposure position.